Alzheimer's disease (AD) is the most common form of dementia in the elderly. AD is clinically characterized by progressive loss of memory, behavior impairment and decline of cognitive function. According to the World Health Organization (WHO), approximately 18 million people worldwide have Alzheimer's disease. By 2025, this estimate is projected to grow to 34 million people, with the highest increase expected among developing countries.
Neuropathological features of AD, and other neurodegenerative diseases, include neurofibrillary tangles, deposition of misfolded proteins in plaques and neuronal loss in affected brain regions. These pathological changes result in a profound loss of neurons and synapses over the course of the disease, thereby contributing to a progressive reduction in the functional capacity of the patient.